Herbal catalog

Vitamin B6 (Commercial distribution prohibited)

Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Vitamin B6 (pyridoxine) is required for the synthesis of the neurotransmitters serotonin and norepinephrine, and for myelin formation.

Pyridoxine deficiency in adults principally affects the peripheral nerves, skin, mucous membranes, and the blood cell system. In children, the central nervous system (CNS) is also affected. Deficiency can occur in people with uremia, alcoholism, cirrhosis, hyperthyroidism, malabsorption syndromes, congestive heart failure (CHF), and in those taking certain medications.

Mild deficiency of vitamin B6 is common. Major sources of vitamin B6 include: cereal grains, legumes, vegetables (carrots, spinach, peas), potatoes, milk, cheese, eggs, fish, liver, meat, and flour.

Pyridoxine is frequently used in combination with other B vitamins in vitamin B complex formulations.

Synonyms

2-Methyl-3-hydroxy-4,5-dihydroxymethylpyridine, 5-hydroxy-6-methyl-3,4-pyridinedimethanol [65-23-6], Adermine Hydrochloride, B Complex Vitamin, B6, B (6), Bio Zinc, Vicotrat, Beesix, Benadon, Bexivit, Bonadon N, Hexobion 100, Naturetime B6, Pyridoxal, Pyridoxal Phosphate, Pyridoxal-5-Phosphate, Pyridoxamine, Pyridoxine HCl, Pyridoxine Hydrochloride, Pyroxin, Rodex, Vita-Valu, Vitabee 6, Vitamin B-6.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Grade*

Hereditary sideroblastic anemia

Pyridoxine supplements are effective for treating hereditary sideroblastic anemia under the supervision of a qualified healthcare provider.

Preventing adverse effects in people taking cycloserine (Seromycin�)

Cycloserine is a prescription antibiotic that may cause anemia, peripheral neuritis or seizures by acting as a pyridoxine antagonist or increasing excretion of pyridoxine. Requirements for pyridoxine may be increased in patients receiving cycloserine. Pyridoxine 100-300 milligrams daily taken in divided doses may be recommended by a healthcare provider to prevent these adverse effects.

Pyridoxine deficiency/ neuritis

Pyridoxine supplements are effective for preventing and treating pyridoxine deficiency and neuritis due to inadequate dietary intake, certain disease states, or deficiency induced by drugs such as isoniazid (INH) or penicillamine. Dietary supplements should be taken under the guidance of a qualified healthcare provider.

Pyridoxine-dependent seizures in newborns

Pyridoxine-dependent seizures in newborns can result from use of high-dose pyridoxine in pregnant mothers or from genetic (autosomal recessive) pyridoxine dependency. Refractory seizures in newborns that are caused by pyridoxine dependence may be controlled quickly with intravenous administration of pyridoxine by a qualified healthcare provider.

Akathisia (movement disorder)

Some prescription drugs called neuroleptics, which are used in psychiatric conditions, may cause movement disorders as an unwanted side effect. Vitamin B6 has been studied for treatment of acute neuroleptic-induced akathisia (NIA) in schizophrenic and schizoaffective disorder patients. Preliminary results indicate that high doses of vitamin B6 may be useful additions to the available treatments for NIA, perhaps due to its combined effects on various neurotransmitter systems. Further research is needed to confirm these results.

Angioplasty

There are conflicting findings about the potential benefit or harm of taking folic acid plus vitamin B6 and vitamin B12 following angioplasty. Further research is needed before a recommendation can be made.

Asthma

Preliminary research suggests that children with severe asthma might have inadequate pyridoxine status. Theophylline, a prescription drug used to help manage asthma, seems to lower pyridoxine levels. Studies of pyridoxine supplementation in asthma patients taking theophylline yield conflicting results. Further research is needed before a conclusion can be drawn.

Attention deficit-hyperactivity disorder (ADHD)

Some research suggests that pyridoxine supplementation alone or in combination with high doses of other B vitamins might help ADHD. Other studies show no benefit. Further research is needed before a conclusion can be drawn.

Birth outcomes

Studies of birth outcomes with vitamin B6 supplementation during pregnancy yield mixed results. Further well-designed clinical trials might be helpful in this area.

Cardiovascular disease / hyperhomocysteinemia

High homocysteine levels in the blood (hyperhomocysteinemia) are a risk factor for cardiovascular disease, blood clotting abnormalities, myocardial infarction, and ischemic stroke. Taking pyridoxine supplements alone or in combination with folic acid has been shown to be effective for lowering homocysteine levels. However, it is not clear if lowering homocysteine levels results in reduced cardiovascular morbidity and mortality. Until definitive data is available, the current recommendation is screening of 40 year-old men and 50 year-old women for hyperhomocysteinemia. Decreased pyridoxine concentrations are also associated with increased plasma levels of C-reactive protein (CRP). CRP is an indicator of inflammation that is associated with increased cardiovascular morbidity in epidemiologic studies. Investigation of more renal transplant recipients undergoing longer treatment with Vitamin B6 is needed as study results conflict.

Carpal tunnel syndrome

Preliminary data suggests that large doses of vitamin B6 may be helpful for carpal tunnel syndrome. Well-designed clinical trials are needed before a firm conclusion can be drawn.

Depression

Preliminary evidence suggests that because pyridoxine increases serotonin and GABA levels in the blood, it may benefit people in dysphoric mental states. Well-designed clinical trials are needed to confirm potential benefit.

Hyperkinetic cerebral dysfunction syndrome

There is preliminary evidence that pyridoxine supplementation might benefit hyperkinetic children who have low levels of blood serotonin. Further research is needed to confirm these results.

Immune system function

Vitamin B6 is important for immune system function in older individuals. One study found that the amount of vitamin B6 required to reverse immune system impairments in elderly people was more than the current recommended dietary allowance (RDA). Well-designed clinical trials on vitamin B6 supplementation for this indication are needed before a recommendation can be made.

Kidney stones (nephrolithiasis)

Pyridoxine alone, or taken with magnesium, may decrease urinary oxalate levels, which can contribute to a certain type of kidney stones. Higher pyridoxine intake has been associated with decreased risk of kidney stone formation in women but not in men with no history of stone formation. Benefit has not been proven in other types of kidney stones such as those associated with high urinary calcium, phosphorus, and creatinine. Further data is needed before a firm conclusion can be drawn.

Lactation suppression

Study results of pyridoxine used to suppress lactation yield mixed results. Well-designed clinical trials are needed before a firm conclusion can be drawn.

Lung cancer

Epidemiological research suggests that male smokers with higher serum levels of pyridoxine may have a lower risk of lung cancer. Well-designed clinical trails of pyridoxine supplementation are needed to confirm these results and supplementation is not standard therapy at this time.

Pregnancy-induced nausea and vomiting

Studies of the use of pyridoxine alone or in combination with other antinausea treatments in pregnant women yield conflicting results. Further research is needed before a recommendation can be made.

Premenstrual syndrome (PMS)

There is some evidence that taking pyridoxine orally may improve symptoms of PMS such as breast pain or tenderness (mastalgia) and PMS-related depression or anxiety in some patients. Further research is needed before a recommendation can be made.

Preventing vitamin B6 deficiency associated with taking birth control pills

The need for vitamin B6 supplementation in women taking birth control pills has not been proven although some studies show decreased pyridoxine levels in these women. Supplementation of B6 should be approached cautiously since the long-term effect of such therapy is uncertain.

Tardive dyskinesia

Pyridoxine has some antioxidant effects, which theoretically may benefit patients with tardive dyskinesia. Further research is needed before a recommendation can be made.

Autism

Studies of B6 supplementation alone or in combination with magnesium have not been shown to benefit autism. Autism should be treated by a qualified healthcare provider.

Stroke reoccurrence

Pyridoxine alone or in combination with B12 and folic acid orally does not seem to be useful for preventing stroke recurrence.

Key to grades

A Strong scientific evidence for this use

B Good scientific evidence for this use

C Unclear scientific evidence for this use

D Fair scientific evidence against this use (it may not work)

F Strong scientific evidence against this use (it likely does not work)

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acne, alcohol intoxication, allergies, appetite stimulation, arthritis, cancer prevention, chorea, conjunctivitis, cystitis, diabetic neuropathy, diuresis, dizziness, Down syndrome, high cholesterol, improving dream recall, infertility, menopausal symptoms, migraine headaches, motion sickness, muscle cramps, mushroom poisoning, night leg cramps, psychosis, radiation sickness, sickle cell anemia, skin conditions.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older):

Recommended daily allowances (RDAs) of vitamin B6 : Males (19-50 years) 1.3 milligrams; (51 years and older) 1.7 milligrams; females (19-50 years) 1.3 milligrams; (51 years and older) 1.5 milligrams. Some researchers think the RDA for women 19-50 years should be increased to 1.5-1.7 milligrams per day. Pregnant women, 1.9 milligrams; and lactating women, 2 milligrams.

Recommended maximum daily intake of vitamin B6 : Adults, pregnant and lactating women (over 18 years) 100 milligrams. A doctor and pharmacist should be consulted for dosing in other conditions.

Children (younger than 18 years):

Recommended daily allowances (RDAs) of vitamin B6 : Infants (0-6 months) 0.1 milligrams; (7-12 months) 0.3 milligrams; children (1-3 years) 0.5 milligrams; (4-8 years) 0.6 milligrams; (9-13 years) 1 milligram; males (14-18 years) 1 milligram per day; females (14-18 years) 1.2 milligrams per day.

Recommended maximum daily intake of vitamin B6 : Children (1-3 years) 30 milligrams; (4-8 years) 40 milligrams; (9-13 years) 60 milligrams. Males, females, pregnant and lactating females (14-18 years) 80 milligrams.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Patients should avoid vitamin B6 products if they are sensitive or allergic to any of their ingredients.

Side Effects and Warnings

Some individuals seem to be particularly sensitive to vitamin B6 and may have problems at lower doses. Overall, pyridoxine is generally considered safe in adults and children when used appropriately at recommended doses. Avoid excessive dosing.

Acne, skin reactions, allergic reactions, and photosensitivity have been reported.

Nausea, vomiting, abdominal pain, loss of appetite, and increased liver function test results (serum aspartate transaminase (AST, SGOT)) have been reported.

Headache, paresthesia, somnolence, and sensory neuropathy have been reported.

Breast soreness or enlargement, decreased serum folic acid levels, seizures after large doses, hypotonia and respiratory distress in infants have also been reported.

Pregnancy and Breastfeeding

Pregnancy : Vitamin B6 is likely safe when used orally in doses not exceeding the recommended dietary allowance (RDA). The RDA for pregnant women is 1.9 milligrams per day. Vitamin B6 is possibly safe when used orally and appropriately in amounts exceeding the recommended dietary allowance. For relief of severe nausea in early pregnancy, 30-75 milligrams per day has been used. A special sustained-release multi-ingredient product providing pyridoxine 75 milligrams per day is FDA-approved for use in pregnancy. However, it should not be used long-term or without medical supervision and close monitoring or in more excessive doses. There is some concern that high-dose maternal pyridoxine can cause neonatal seizures.

Breastfeeding : Vitamin B6 is likely safe when used orally in doses not exceeding the recommended dietary allowance (RDA). The RDA in lactating women is 2 milligrams per day. There is insufficient reliable information about the safety of pyridoxine when used in higher doses in lactating women. Because most lactating women do not consume the RDA of vitamin B6 in their normal diets and do not provide totally breast-fed infants with the RDA of this vitamin, doses as high as 4 milligrams per day of vitamin B6 may be recommended although benefits have not been well proven.

ARTICLE SECTIONS

Methodology

This patient information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Monograph methodology

Selected references

Clarke R, Armitage J. Vitamin supplements and cardiovascular risk: review of the randomized trials of homocysteine-lowering vitamin supplements. Semin.Thromb.Hemost. 2000;26(3):341-348.
Findling RL, Maxwell K, Scotese-Wojtila L, et al. High-dose pyridoxine and magnesium administration in children with autistic disorder: an absence of salutary effects in a double-blind, placebo-controlled study. J.Autism Dev.Disord. 1997;27(4):467-478.
Leeda M, Riyazi N, de Vries JI, et al. Effects of folic acid and vitamin B6 supplementation on women with hyperhomocysteinemia and a history of preeclampsia or fetal growth restriction. Am.J.Obstet.Gynecol. 1998;179(1):135-139.
Lerner V, Miodownik C, Kaptsan A, et al. Vitamin B(6) in the treatment of tardive dyskinesia: a double-blind, placebo-controlled, crossover study. Am.J.Psychiatry 2001;158(9):1511-1514.
Lerner V, Bergman J, Statsenko N, et al. Vitamin B6 treatment in acute neuroleptic-induced akathisia: a randomized, double-blind, placebo-controlled study. J.Clin.Psychiatry 2004;65(11):1550-1554.
Miodownik C, Lerner V, Statsenko N, et al. Vitamin B6 versus mianserin and placebo in acute neuroleptic-induced akathisia: a randomized, double-blind, controlled study. Clin Neuropharmacol.
Nye C, Brice A. Combined vitamin B6-magnesium treatment in autism spectrum disorder. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD003497.
Rimm EB, Willett WC, Hu FB, et al. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA 2-4-1998;279(5):359-364.
Sahakian V, Rouse D, Sipes S, Rose N, et al. Vitamin B6 is effective therapy for nausea and vomiting of pregnancy: a randomized, double-blind placebo-controlled study. Obstet.Gynecol. 1991;78(1):33-36.
Schnyder G, Roffi M, Flammer Y, et al. Effect of homocysteine-lowering therapy with folic acid, vitamin B12, and vitamin B6 on clinical outcome after percutaneous coronary intervention: the Swiss Heart study: a randomized controlled trial. JAMA 8-28-2002;288(8):973-979.
Thaver D, Saeed MA, Bhutta ZA. Pyridoxine (vitamin B6) supplementation in pregnancy. Cochrane Database Syst
Vermeulen EG, Stehouwer CD, Twisk JW, et al. Effect of homocysteine-lowering treatment with folic acid plus vitamin B6 on progression of subclinical atherosclerosis: a randomised, placebo-controlled trial. Lancet 2-12-2000;355(9203):517-522.
Vutyavanich T, Wongtra-ngan S, Ruangsri R. Pyridoxine for nausea and vomiting of pregnancy: a randomized, double-blind, placebo-controlled trial. Am.J.Obstet.Gynecol. 1995;173(3 Pt 1):881-884.
Woodside JV, Yarnell JW, McMaster D, et al. Effect of B-group vitamins and antioxidant vitamins on hyperhomocysteinemia: a double-blind, randomized, factorial-design, controlled trial. Am.J.Clin.Nutr. 1998;67(5):858-866.
Wyatt KM, Dimmock PW, Jones PW, et al. Efficacy of vitamin B-6 in the treatment of premenstrual syndrome: systematic review. BMJ 5-22-1999;318(7195):1375-1381.